Hi r0ss0,

> If I buy the v4 now(as 2022-4-27), do I pay for the v5 upgrade or it will be a free upgrade?

It would be a paid upgrade. There will be a "grace period" where if you purchase v4 within a couple of months of the v5 release you will get a free upgrade to v5. But the v5 beta period has only just recently started, the full release is quite a ways off yet definitely more than a couple of months.

So a v4 purchase right now would not be in the grace period time for getting a free v5 upgrade.

- Michael